[SR-3860] error: ambiguous use of operator '-'

[krzyzanowskim]

Previous ID	SR-3860
Radar	rdar://problem/30393457
Original Reporter	@krzyzanowskim
Type	Bug

Attachment: Download

Environment

Swift 3.0.2

Additional Detail from JIRA

Votes	0
Component/s	Compiler
Labels	Bug, 3.0Regression, TypeChecker
Assignee	None
Priority	Medium

md5: dc1a3e25eed7f5c5f470127841c056e3

Issue Description:

Given sample does not compile. It does compile for the "+" operation, though.

let arr:[UInt32] = [1,2,3]

_ = UInt32(1 - arr[Int(1)]) // error: ambiguous use of operator '-'
_ = UInt32(1 - arr[1])      // ok

Untitled 12.swift:4:14: error: ambiguous use of operator '-'
_ = UInt32(1 - arr[Int(1)]) // error: ambiguous use of operator '-'
             ^
Swift.-:1:13: note: found this candidate
public func -<T : Strideable>(lhs: T, rhs: T) -> T.Stride
            ^
Swift.-:1:13: note: found this candidate
public func -<T : _DisallowMixedSignArithmetic>(lhs: T, rhs: T) -> T._DisallowMixedSignArithmetic
            ^

[jckarter]

@swift-ci create

[belkadan]

Not a regression, at least?

[rintaro]

Looks like 3.0 regression.
This compiles in Swift 2.3.